Shaft furnace charger



Feb. 8, 1966 J. c. LQNG 3,233,757

SHAFT FURNACE CHARGER Filed Aug. 20, 1964 2 Sheets-Sheet 1 c WK INVENTOR.

% Q JOSEPH c. LONG ATTORNEY Feb. 8, 1966 .1. c. LONG 3,233,757

SHAFT FURNACE CHARGER Filed Aug. 20, 1964 2 Sheets-Sheet 2 33 INVENTOR.

J7 3/ J5 JOSEPH c. LONG A TTORNEV United States Patent 3,233,757 SHAFT FURNAQE CHARGER Joseph C. Long, Niagara Falls, N.Y., assignor to Union Carbide Corporation, a corporation of New York Filed Aug. 20, 1954, Ser. No. 390,865

3 Claims. (Cl. 21435) This invention relates to a charger for use with a kiln or furnace and it refers more particularly to a charging gate system for use with a shaft furnace operating under sub-atmospheric top pressure. It is the general procedure in the operation of shaft furnaces to provide the top of the furnace with a double or even triple vertical series of chambers separated from each other by conical valves which are independently operated. When operating these valves in a desired se quence, solid materials can be passed through the chambers and into the furnace without a significant loss of gas pressure Within the furnace. Since such furnaces are generally operated at greater than atmospheric pressures and since the exhaust gases are invariably recovered, the conical valves are designed to withstand any gas pressure against the underside of the cone. This pressure or force is thus in a direction which tends to close and seat the cones.

In the shaft furnace described-in United States Patent 2,933,297, the combustion and reaction gases are withdrawn by suction at the top of the shaft furnace. Such charging systems as exemplified by this patent are designed to withstand gas pressure on the top of the cones. Pressure in this direction tends to open the cones and generally results in leakage.

A further disadvantage of the cone-type closure is that the solid charge material slides over and abrades away the seating surfaces thus making it difiicult to maintain a gastight seal.

It is therefore the principal object of the invention to provide a self-sealing charging valve for use on shaft furnaces operating under sub-atmospheric top pressure.

It is another object of the invention to provide a charging valve which enables the solid charge material to pass therethrough without contacting or abrading the seating surfaces of the valve.

These and other objects and advantages of the invention are achieved by apparatus comprising a cylindrical segment plate supported by two or more sector plates, the assembly being rotatable around a horizontal axis, the cylindrical segment plate sliding over an open-ended conduit, the transverse end section of which conforms to the cylindrical form of the segment plate; hopper means of smaller cross-sectional area at its exit than the conduit disposed so as to introduce charge material into the conduit without contact with the end or the walls thereof; and means to rotate the cylindrical sector assembly around its axis.

In the accompanying drawing:

FIGURE 1 is a vertical elevational view through a shaft furnace (partially shown in section) provided with two chargers or gate assemblies of the invention taken transverse to the axis of rotation of the gate assemblies;

FIGURE 2 is an enlarged sectional view through one of the gate assemblies in FIG. 1, and

FIGURE 3 is a vertical sectional view taken along line 33 of FIGURE 2.

With reference to the drawing and particularly to FIG- URES l and 2, there is shown a gate assembly including two segment plates 12 and 14 which are rotatably supported by a pair of suitable bearings 16 and 18 on each end of shaft 20. As best shown in FIG. 2, the lower ends of the segment plates 12 and 14 are rigidly connected together by a cylindrical sector gate plate 22 which controls the flow of charge material from hopper 24.

A cylindrical sector seal plate 26 and its supporting side rib plates 28 and 30 (seal assembly) are loosely fastened to the segment plates 12 and 14 so as to move rotatably with the gate assembly 10 and to allow a small degree of movement in a radial direction. The gate assembly 10 and the seal plate and its supporting rib plates 28 and 30 as well as the lower portion of the hopper 24 are enclosed Within a suitable gas tight housing 32. As best shown in FIG. 3, bars 34 and 36 secured to the cylindrical wall of the housing 32 form the stationary sealing members upon which the seal plate 26 seats and slides. The upper end of a connecting conduit 38 coincides in contour with the upper surface of the bars 34 and 36, and when the gate assembly 10 is in the closed position it is directly contacted and sealed by the seal plate 26. If desired, the housing 32 may be suitably equipped with capped inspection ports 40 and 42 and a pressure manometer connecting means 43.

Inner replaceable and adjustable wear bars such as indicated by the numerals 31, 33, 35 and 37 are provided all around the upper periphery of the connecting conduit 38. These bars are suitably fastened to the conduit 38, such as, for instance, by fasteners and can be adjusted to compensate for any wear. Access doors 39 and 41, as best shown in FIG. 3 are suitably provided on the sides of the housing 32 to facilitate the inspection and replacement of the wear bars 31, 33, 35 and 37. Of course, access door openings 45 and 47 must also be provided in the Walls of the housing 32.

The gate assembly 10 may be operated by any suitable power means such as, for instance, hydraulic or pneumatic actuator means, or as shown in FIG. 1 by an electric motor, suitable gear head 44 and pulley, the latter of which is suitably connected to the shaft 20 by means of a connecting belt or chain 46. The entire two-gate assembly 1t and 19 illustrated in FIG. 1 is completely enclosed to form a vacuum-tight seal on the top of the furnace generally depicted as 48 when either gate and seal assembly is in the closed position.

If desired, a suitable cone 50 may be utilized with the apparatus of the invention if it is necessary for the charge material to be spread over the full cross-sectional area of the shaft furnace 48.

The operation of the gate and seal assemblies of the invention will be best understood with reference to FIG. 1. The charge material to be fed into the furnace 4% is charged into the upper hopper 24. Of course, initially both gate and seal assemblies are in the closed positions; that is, with the seal plates 26 and 26' fully covering the opening of conduits 33 and 38". Thus, the system is gastight due to the pressure differential existing on the upper and lower faces of the seal plates 26 and 26. The pressure in hopper 24' and housing 32' will invariably be atmospheric and the pressure in hopper 24 and housing 32 will depend on previous operation cycles and may also be equal to atmospheric or as low as that in the furnace 43.

The charge material to be passed into the furnace 48 is suitably disposed in the hopper 24' through top opening 52 whereupon it accumulates on the sector gate plate 22'. The gate assembly it) and the seal assembly (seal plate 26' and rib plates 28 and 30') are then rotated together as a unit thus exposing conduit 38' and allowing the charge material to pass into hopper 24 and rest upon the sector gate plate 22. Since the exit end of hopper 24 is of smaller transverse dimensions than conduit 33, the solid charge material does not come into contact with the seating surfaces of the end of said conduit. After the charge has passed into lower hopper 24, the upper gate and seal assembly is rotated back to the closed position. During rotation the sliding contact between the seal plate 26' and the seating area of conduit 38', and sealing bars 54' and 36' (not shown), serves to remove any dust that may have settled on these latter surfaces. Thus, the solid charge material cannot destroy the tightness of the seal as is true with prior cone-type seals. The seal plate 26 being free to move radially will seat itself over conduit 38 by the action of its own weight (gravity) and by suction or negative pressure created by an induced draft fan operation.

The same procedure is repeated with the lower gate and seal assemblies whereupon the charge passes through conduit 38 and into the furnace 48. Gas within housing 32 and hopper 24 is withdrawn into the furnace 48 when the lower gate and seal assemblies are moved to the open position, thus creating a pressure differential on the two faces of the upper seal plate 26 causing same to seat tightly over the opening of upper conduit 38. Thus, the passage of any gas through conduit 38 assists in causing flow of the charge material therethrough. When the upper gate and seal assemblies are again opened in the next operating cycle, gas entering the lower hopper 24 and housing 32 will create a pressure diiferential across the lower seal plate 26, further seating the plate 26 on conduit 38. T he upper hopper 24' is, of course, refilled as soon as the upper gate and seal assemblies have been reclosed. As illustrated in FIG. 1, the double charging assembly makes it possible to batch charge a kiln or furnace on a continuous basis without loss of draft since the gate and seal assemblies are synchronized so that as one is open the other is closed and thus no loss can occur which would otherwise affect the kiln or furnace operation.

If desired, an gas introduced along with charge material into the lower hopper 24 may be suitably removed through a separate off-take pipe (not shown) connected to housing 32 rather than through the furnace 48 when the lower gate and seal assemblies are opened. By this construction, even momentary increases in pressure in th top of the furnace can be avoided.

It should be apparent from the foregoing that many modifications and changes in the construction and arrangement of the parts may be made without departing from the spirit and scope of the invention and therefore it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. For example, the conduits may be of any desired cross-sectional shape; i.e., rectangular, oval, circular, etc.

What is claimed is:

1. In combination, a self-sealing hopper and gate assembly suitable for use in charging solid and plastic materials into a shaft furnace operating with a top pressure less than atmospheric which comprises, a first pair of hanger plates rotatably supported about a shaft, a cylindrical sector' gate plate rigidly secured to the lower ends of said first pair of hanger plates, a second pair of substantially shorter hanger plates loosely fastened to the lowermost portion of said first pair of hanger plates, a cylindrical sector seal plate rigidly secured to the lower ends of said second pair of hanger'plates, and means for rotating said first pair of hanger plates and said cylindrical sector gate plate about said shaft, said second pair of hanger plates and said cylindrical sector seal plate being adapted to move rotatably with said first pair of hanger plates and said cylindrical sector gate plate, said cylindrical sector gate plate adapted to control the flow of said charge materials to the lower discharge section of a hopper, the lower discharge section of said hopper being enclosed within a gas-tight housing which conforms in shape with the cylindrical form of said sector gate and seal plates and which is connected to an open ended conduit, said dis-. charge section of said hopper being positioned just above said sector gate and seal plates and said open ended conduit which leads to said shaft furnace and being smaller in cross-sectional area at its exit end than the cross-sectional area of said conduit whereby solid and plastic charge material which is dispensed into saidshaft furnace from said hopper does not contact or abrade the walls of said housing and the seating surfaces of said gate and seal plates.

2,. The combination of claim ll wherein wearing bars are releasably secured about the upper periphery of said conduit whereby said bars can be adjusted to compensate for any wear.

3. The combination of claim 2 wherein access openings and doors are provided on the sides of said gas tight housing to facilitate the inspection and replacement of said wearing bars.

HUGO O. SCHULZ, Primary Examiner. 

1. IN COMBINATION, A SELF-SEALING HOPPER AND GATE ASSEMBLY SUITABLE FOR USE IN CHARGING SOLID AND PLASTIC MATERIALS INTO A SHAFT FURNACE OPERATING WITH A TOP PRESSURE LESS THAN ATMOSPHERIC WHICH COMPRISES, A FIRST PAIR OF HANGER PLATES ROTATABLY SUPPORTED ABOUT A SHAFT, A CYLINDRICAL SECTOR GATE PLATE RIGIDLY SECURED TO THE LOWER ENDS OF SAID FIRST PAIR OF HANGER PLATES, A SECOND PAIR OF SUBSTANTIALLY SHORTER HANGER PLATES LOOSELY FASTENED TO THE LOWERMOST PORTION OF SAID PAIR OF HANGER PLATES, A CYLINDRICAL SECTOR SEAL PLATES RIGIDLY SECURED TO THE LOWER ENDS OF SAID SECOND PAIR OF HANGER PLATES, AND MEANS FOR ROTATING SAID FIRST PAIR OF HANGER PLATES AND SAID CYLINDRICAL SECTOR GATE PLATE ABOUT SAID SHAFT, SAID SECOND PAIR OF HANGER PLATES AND SAID CYLINDRICAL SECTOR SEAL PLATE BEING ADAPTED TO MOVE ROTATABLY WITH SAID FIRST PAIR OF HANGER PLATES AND SAID CYLINDRICAL SECTOR GATE PLATE, SAID CYLINDRICAL SECTOR GATE PLATE ADAPTED TO CONTROL THE FLOW OF SAID CHARGE MATERIALS TO THE LOWER DISCHARGE SECTION OF A HOPPER, THE LOWER DISCHARGE SECTION OF SAID HOPPER BEING ENCLOSED WITHIN A GAS-TIGHT HOUSING WHICH CONFORMS IN SHAPE WITH THE CYLINDRICAL FORM OF SAID SECTOR GATE AND SEAL PLATES AND WHICH IS CONNECED TO AN OPEN ENDED CONDUIT, SAID DISCHARGE SECTION OF SAID HOPPER BEING POSITIONED JUST ABOVE SAID SECTOR GATE AND SEAL PLATES AND SAID OPEN ENDED CONDUIT WHICH LEADS TO SAID SHAFT FURNACE AND BEING SMALLER IN CROSS-SECTIONAL AREA AT ITS EXIT END THAN THE CROSS-SECTIONAL AREA OF SAID CONDUIT WHEREBY SOLID AND PLASTIC CHARGE MATERIAL WHICH IS DISPENSED INTO SAID SHAFT FURNACE FROM SAID HOPPER DOES NOT CONTACT OR ABRADE THE WALLS OF SAID HOUSING AND THE SEATING SURFACES OF SAID GATE AND SEAL PLATES. 